Preparation and in vitro Studies of Stealth PEGylated PLGA Nanoparticles as Carriers for Arsenic Trioxide

The aim of this study was to prepare arsenic trioxide （ATO）-loaded stealth PEGylated PLGA nanoparticles （PEG-PLGA-NPs） and to assess the merits of PEG-PLGA-NPs as drug carriers for ATO delivery. PEG-PLGA copolymer was synthesized with methoxypolyethyleneglycol （Mw=5000）, D, L-lactide, and glycolide by the ring-opening polymerization method. Amorphous ATO was transformed into cubic crystal form to increase its solu-bility in the organic solvent. ATO-loaded PEG-PLGA-NPs were prepared by the modified spontaneous emulsification solvent diffusion （SESD） method, and the main experimental factors influencing the characteristics of nanopar- ticles were investigated, to optimize the preparation. To confirm the escape of PEG-PLGA-NPs from phagocytosis by phagocytes, PEG-PLGA-NPs labeled rhodamine B uptake by murine peritoneal macrophages （MPM） were analyzed by flow cytometry. The results showed that the physicochemical characteristics of PEG-PLGA-NPs were affected by the type and concentration of the emulsifiers, polymer concentration, and drug concentration. ATO-loaded PEG-PLGA-NPs, with particle size of 120.8nm, zeta potential of-10.73mV, encapsulation efficiency of 73.6%, and drug loading of 1.36%, were prepared under optimal conditions. The images of transmission electron micros-copy （TEM） indicated that the optimized nanoparticles were near spherical and without aggregation or adhesion. The release experiments in vitro showed the ATO release from PEG-PLGA-NPs exhibited consequently sustained release for more than 26d, which was in accordance with Higuchi equation. The uptake of PEG-PLGA-NPs by MPM was found to decrease markedly compared to PLGA-NPs. The experimental results showed that PEG-PLGA-NPs were potential nano drug delivery carriers for ATO.

Pharmaceutical Characteristics of Daunorubicin Stealth Liposomes

This report studied on pharmaceutical characteristics of the stealth liposome containing dau-norubicin (DNR). The shape, size, entrapment efficiency and stability of the daunorubicin stealth liposomes (DNRSL) were examined. Visible spectrophotometry and the HPLC method were established for determination of the DNR in the DNRSL. The release of DNR from DNRSL in HBS (pH 7.5) and rat serum at 37 oC were examined. The results showed that the DNRSL had high entrapment efficiency (>85%), small size and slow release.

Controlled Drug Release Studies of Atenolol Using Differently Sulfonated Acryloxyacetophenone and Methyl Methacrylate Copolymer Resins as Drug Carriers

2-Acryloxyacetophenone （AAP） was prepared and subjected to suspension polymerization with methyl methacrylate （MMA） using azobisisobutyronitrile （AIBN） as free radical initiator. The differently sulfonated AAP-MMA cross-linked copolymer cationic exchange resins were prepared by sulfonation with concentrated sulphuric acid at 70 ~C. Several characteristics of the prepared resins were evaluated, i.e. FTIR, the ion-exchange capacity （IEC）, thermo gravimetric analysis （TGA）, particle size distribution and microscopic morphology. The resin characteristics were altered with degree of sulfonation, providing that differently sulfonated resins could be prepared. The behavior of atenolol （ATL） loading and in vitro release in the USP stimulated gastric and intestinal fluids of the obtained resins were evaluated. The drug loaded in the resin increased with increasing degree of sulfonation and hence the drug binding site in resin employed. The drug release was lower from the resins with higher content of sulfonic group due to the increase in the diffusive path depth. The drug release was a little lower in stimulated gastric fluid （SGF） than in stimulated intestinal fluids （SIF）. The basic groups, ionized to a little greater extent in SGF and preferred binding with the resin rather than releasing. Hence, the differently sulfonated resins could be utilized as novel carriers for drug delivery.

Formulation and evaluation of a bioadhesive patch for buccal delivery of tizanidine

Tizanidine hydrochloride(THCl)is an antispasmodic agent which undergoes extensive first pass metabolism making it a possible candidate for buccal delivery.The aim of this study was to prepare a monolayered buccal patch containing THCl using the emulsification solvent evaporation method.Fourteen formulations were prepared using the polymers Eudragit■ RS 100 or EudragitB RL 100 and chitosan.Polymer solutions in acetone were combined with a THCl aqueous solution(in some cases containing chitosan)by homogenization at 9000 rpm for 2 min in the presence of triethyl citrate as plasticizer and cast in novel Teflon molds.Physicochemical properties such as film thickness,in vitro drug release and in vitro mucoadhesion were evaluated after which permeation across sheep buccal mucosa was examined in terms of flux and lag time.Formulations prepared using a Eudragit■polymer alone exhibited sa tisfactory physicomechanical properties but lacked a gradual in vitro drug release pattern.Incorporation of chitosan into formulations resulted in the formation of a porous structure which did exhibit gradual release of drug.In conclusion,THCl can be delivered by a buccal patch formulated as a blend of Eudragit■ and chitosan,the latter being necessary to achieve gradual drug release.

A novel cataplasma matrix of traditional Chinese medicine

The aim of this paper was to develop a cataplasma matrix that can be applicable to both watersoluble and liposoluble drugs.The gellan gum and konjaku were employed as the scaffold materials of the matrix.With polyacrylic acid sodium and oligosaccharides as tacktifier,the formula of the cataplasma matrix was optimized in the orthogonal method as:gellan gum 0.4 g,xanthan gum 0.03 g,konjac glue 0.1 g,glycerin 4 g,Gluco-Adhesive T(GAT)6 g,Gluco-Adhesive E(GAE)6 g,polyacrylic acid sodium 0.22 g,and sorbitol 3 g.The 180°peel strength,the tensile strength and the elongation at break was 3.043 N,0.275 MPa and 91.05%,respectively.Furthermore,the drug-compatibilities of the matrix were investigated with baicalin,berberine and curcumin,which were used as the models of hydrophilic,poor-water-soluble and hydrophobic ingredients.The drug contents could reach 4.12%,2.42%and 3.75%,while the in vitro release rate were measured as,361.79,55.85 and 104.41μg·cm^(-2)·h^(-1)for baicalin,berberine and curcumin,respectively.These results indicated that the obtained matrix had good drug-compatibility and drug-release properties for different ingredients.